MELBOURNE, Australia (AP) — Milos Raonic was just overwhelming Alexander Zverev with consistency, compounding the frustration with every service break.

Roanic dropped serve in the opening game of their fourth-round match at the Australian Open but then went on a roll, winning eight straight games before fourth-seeded Zverev held serve.

No let up. Raonic held and then broke the 21-year-old German player's serve again to lead 4-1 and that's when Zverev lost it.

At the change of ends he destroyed his racket by smacking it into the court eight times, then tossing it away.

The angry outburst only served to highlight Raonic's dominance.

"I played incredible today," the 2016 Wimbledon runner-up said. "I did a lot of things very well. Proud of that."

And so he should be. He's into the Australian Open quarterfinals for the fourth time. And he's achieved that from a tough part of the draw.

He opened with a win over the enigmatic Nick Kyrgios, who had all the home-won support, and followed that up by coming back to beat three-time major winner Stan Wawrinka in four tiebreak sets. The 16th-seeded Raonic then beat Pierre-Hugues Herbert in three tiebreakers.

At 28, Raonic feels like he's on the verge of being back as a contender at the majors. Zverev, an undoubted talent, is yet to beat a top 20 player at a Grand Slam.

Raonic was so consistent with his serve — 15 aces, one double-fault, 16 of 19 first serves into play for the second set — and kept his unforced error count down to 24 for the match. He said he could sense his rival's growing rage.

"It was pretty clear what was going on," he said. "It can have an effect a lot of different ways. You know, if you're a top guy and you do that against somebody who doesn't have experience, it might sort of cause them to retreat a little bit.

"I have sort of faced that situation, and I was also ahead at that point, so I was just really focusing on myself."

Zverev got the inevitable warning for racket abuse, took a break at the end of the second set and returned from the locker room a much calmer, more composed player.

"Yeah, it made me feel better," Zverev said. "I was very angry, so I let my anger out."

Zverev lost only one point in his first four service games in the third set, but then Raonic stepped up the pressure again.

"I played bad. The first two sets especially I played horrible," Zverev said. "I mean, it's just tough to name one thing. I didn't serve well, didn't play well from the baseline. Against a quality player like him, it's tough to come back from that."

Zverev saved two match points in the 10th game of the third — one with a short slice backhand that Roanic ran for but couldn't retrieve to end a 29-shot rally and another that clipped the baseline.

But Raonic rallied from 3-1 down in the tiebreaker and finally converted on his fourth match point. He'll next play either No. 11 Borna Coric or No. 28 Lucas Pouille in the quarterfinals.

Earlier U.S. Open Naomi Osaka was a set down again and looking for a bit of inspiration.

She thought of how 20-year-old Stefanos Tsitsipas had stunned 20-time major winner Roger Federer and how Frances Tiafoe has advanced to the quarterfinals for the first time. This helped her pull herself together to reach the last eight, too.

No. 4-seeded Osaka had a 4-6, 6-3, 6-4 fourth-round win over No. 13-seeded Anastasija Sevastova to reach the last eight at a major for the second time. She'll next play sixth-seeded Elina Svitolina, who fended off five break points in a game in the third set that went to deuce 11 times, contained 28 points, and was pivotal in a momentum-swinging 6-2, 1-6, 6-1 win over 2017 U.S. Open finalist Madison Keys.

"I wasn't really sure what to do at a point. I just try to stick in there," Osaka said. "And also I was watching all these kids winning, like, last night Tsitsipas beat Federer and I was like, 'Woah' — so I decided I wanted to do well, too.'

Another win now and there's potential for Osaka to have a rematch of the U.S. Open final against Serena Williams. The seven-time Australian Open champion Williams was playing top-ranked Simona Halep later Monday in the fourth round. The winner of the Williams-Halep contest will meet seventh-seeded Karolina Pliskova, who beat Garbine Muguruzu 6-3, 6-1 in an hour.

Pliskova, who is on a nine-match winning streak, plans to watch on TV: "For sure, it's going to be the match of the tournament so far."

Osaka will be concentrating more now on Svitolina.

Coming off a win at the WTA Finals, Svitolina is aiming to do what Caroline Wozniacki did last year and follow up a title at the season-ending championship with a breakthrough major in Australia.

For a quarter of an hour on Day 8, Svitolina served and served, and served, tossing the ball into the sun, in a desperate bid to hold a game in the third set against Keys.

After that huge hold, she broke the 17th-seeded Keys' serve in at her first opportunity in the next game, and it was all one-way from then on.

"I was happy I could handle the pressure at 1-1 in the third set," Svitolina said. "It was very hard because the sun was just burning my eyes when I was tossing the ball. Very happy I could win that game."

She's taking an 0-3 record in Grand Slam quarterfinals into her next match against Osaka, but is taking a different mindset into the match.

Winning in Singapore "gave me huge boost of confidence, so I don't think about the past anymore," she said. "I only look forward."